lex afm, apexi neo, 440 inj. will this work

mnracer550

New Member
Sep 15, 2010
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Duluth, Minnesota
hey guys, quick question. im going and picking up an apexi afc neo today for a killer price. i already have the lex afm but no 550 inj. will i be able to adj it far enough with the neo for a decent tune? current mods are full turbo back 3'' exhaust. aem widebank. apexi intake. the lexus afm isnt installed yet. iv just had it sitting around for awhile. thanks guys
 

hvyman

Dang Dude! No Way Man.
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Apr 17, 2007
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Fullerton,CA
If your still on stock turbo its not worth it and even with a 57trim it still might would not be worth it unless you had a walbro which at that point you might as well get the 550's so you dont run out of fuel.

Can it be done yes, but its not reccomended.
 

mkIIIman089

Supramania Contributor
Mar 30, 2005
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I wouldn't touch anything until you understand WHY the lex AFM mod works, and the additional mods you need to go with it. The older articles are some of the better ones, and for someone who actually knew what he was doing with the mod, look for John B Lunsford's (jblmk3) old setup.
 

Green7mgte

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Dec 30, 2009
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North Canton, Ohio, United States
^ true story. slap it on and set it rich wont ruin anything driving around for a day. but its not recommended. Waite until you can go standalone or have your wideband gauge installed so you can see exactly what your ratio is doing.. helpful tip also is to install your wideband before the mods so you can see what your "normal" afr is.
 

hvyman

Dang Dude! No Way Man.
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Apr 17, 2007
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Lex/550 mod is an equal 25% fuel and air upgrade. Add just the lex and you will prolly raise the boost at this time and you have a good possibility of running lean.

True story: one of my buddies had a lex and 60-1 trim at 18psi. Him and a another person ran(I wasn't there) and he melted the number 6 piston(I saw the block and piston). This was on stock fuel upgraded turbo and lex.
 

Kai

That Limey Bastard
Staff member
If you add the lexus AFM on its own without the injectors, even with the SAFC Neo, you're still going to run lean. You'd have to run your existing, tired injectors at a much higher duty cycle than they'd be happy with, and still be running the risk of turning your combustion chamber into a plasma cutter. Never cheap out with a 7M. Ever. Not saying you have to spend an assload of money, but the old axiom of 'Fast. Cheap. Reliable. Pick two.' definitely applies.
 

mkIIIman089

Supramania Contributor
Mar 30, 2005
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If the boost remains relatively the same, the addition of ONLY a Lexus AFM will do no harm at all. The ECU has enough capability to correct for the "strange" air sensor data its getting. May also lower fuel cut to compensate, since it modifies the open loop mapping by what learned values its recorded in closed loop, though I have not personally experimented.

As with any mod, always remember to reset the ECU before running it.
 

SideWinderGX

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Aug 8, 2007
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mkIIIman089;1634274 said:
If the boost remains relatively the same, the addition of ONLY a Lexus AFM will do no harm at all. The ECU has enough capability to correct for the "strange" air sensor data its getting. May also lower fuel cut to compensate, since it modifies the open loop mapping by what learned values its recorded in closed loop, though I have not personally experimented.

As with any mod, always remember to reset the ECU before running it.

Wrong.

Fuel trim can only correct up to 20% and that's only because of the O2 sensor feedback. The computer will realize something is wrong when the AFM readings are normal (lexus and supra electronics are the same, difference is the housing) but the afr is wacky.

I wouldn't do it and would advise against it.
 

mkIIIman089

Supramania Contributor
Mar 30, 2005
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Ohio
You say that like you've read it on the interweb, no doubt written by an "expert".

I've tried, tested, and logged all of what I just described, myself. Might want to check yourself before spreading hearsay over tested fact.